1. Field
The present disclosure relates to drive systems and more particularly pertains to a new drive system with a low speed, high torque drive mode and a freewheel mode.
2. Description of the Prior Art
Conveyors have been mounted on trailers to be towed behind motorized vehicles for transport over long distances. Recently, conveyors have been developed that are able to move short distances for the purpose of distributing the material carried on the conveyor belt over an area of ground, rather than simply in a pile at a single location. This movement does not require high speed movement over long distances, but requires a relatively slow and uniform pace of movement over short distances. While this movement does not require the entire conveyor to be moved, and it is common that one end of the conveyor is pinned in a single location while the other end is swung in an arc with respect to the stationary end, and quite often the conveyor apparatus, as well as the material being conveyed on the apparatus, is extremely heavy and requires a significant amount of force to move even these limited distances. Such heavy duty drive systems are typically not suitable for turning at the high speeds encountered when the conveyor is towed on a highway.
Various systems have been developed for these conveyors to permit the two modes of use, with one approach being disclosed in U.S. Pat. No. 5,515,961, which employs a set of wheels for higher speed road travel and a separate set of wheels for the slower movement during conveying operations. While this approach works, the extra set of wheels and the apparatus to deploy those extra wheels add significantly to the cost and weight and overall bulk of the conveyor apparatus, making this approach less than desirable.
Another approach utilizes wheels that are mounted on a support that may be swung between a position in which the wheels are oriented for towing of the conveyor and a position in which the wheels are oriented for causing lateral back and forth motion of one end of the conveyor. This approach generally adds less weight to the conveyor apparatus, the known systems have utilized chains for a system to drive the wheels for the back and forth motion. However, the chains need to be removed or disconnected when the conveyor is to be towed on the road. The chains needed to transfer the significant amount of power required to move the large conveyors are very heavy and cumbersome to install and remove, making the changeover process lengthy, strenuous and somewhat dangerous.
As can be appreciated from the foregoing, drive systems for mobile apparatus, such as conveyors that are mounted on trailers but intended to be capable of a degree of independent movement, present a challenge for designers. It is therefore believed that there is a need for an improved drive system for such apparatus that minimizes size, weight, and effort for converting between modes of operation.